Cone of Silence

A Cone of Silence is a field or zone wherein the sound of the human voice was electronically distorted so that recording and amplifying devices could not reproduce it effectively or clearly. It was also referred to as a "sound-deadening field". The size of a "cone of silence" depended partly on the strength of the electronic impulse broadcast, but for practical purposes it was usually a small area about three to four meters in diameter.

The Dune Encyclopedia outlines a possible background for the Cone of Silence. It states that originally, the cone of silence was developed by Ixian technicians in the fourth millennium, but it apparently proved to be fairly easy for non-Ixian electronic technicians to reproduce. Nevertheless, the Great Houses would apparently hire Ixian masters, likely under the supervision of the House Master of Assassins, to inspect and refurbish the auditory facilities — both recorders and cones — of a residential palace.